feat(ngRepeat): expose the iterating properties over the alias

Expose the properties `$index`, `$first`, `$middle`, `$last`, `$odd` and `$even` as part of the alias

Closes #9582
I like the original idea of reusing the same alias name, the collection is an array and that makes it somehow less problematic in regards to shadowing properties (still not great, but not really bad)
People that need to use this are a very small % of the uses of `ng-repeat` so I am not too worried about a small performance impact